Plate clamp



J. BRYER PLATE CLAMP Nov. 14, 1961 2 Sheets-Sheet 1 Filed Sept. 23, 1958 Vm Nm V INVENTOR 66 A ORNEY5 Nov. 14, 1961 J. BRYER v ,008,

PLATE CLAMP Filed Sept. 23, 1958 2 Sheets-Sheet 2 INVENTOR A ORNEY 3,008,410 Patented Nov. 14, 1961 ice 3,008,410 PLATE CLAMP Jack Bryer, Paramus, N.J., assignor to R. Hoe & Co Inc,

New York, N.Y., a corporation of New York Filed Sept. 23,1958, Ser. No. 762,841

Claims. (Cl. 101---415.1)

This invention relates to plate clamps for holding printing plates on printing cylinders, and more particularly for use with lithographic printing plates or other-comparatively thin, flexible plates.

It is an object of the invention to provide a plate clamping mechanism of;simple construction and requir ing a minimum opening or gap in the cylinder surface for the insertion of the plate end.

It is another object of the invention to provide for faces; 22 and 23 forming cooperating plate end engaging In operation, the plate ends are pre-bent to the form shownlin FIG. 4, the end '10 being bent around so as to fit over the rounded edge '9 on oneside of the gap and 'lie: against the plane surface '11,"-as: indicated, and the other end 26 being bent at an acute angle, as. indicated a mechanism which permits an easy removal of the plate I from the plate cylinder surface by pushing the tail of the plate out of the'op'ening or gap of the cylinder when opening said clamping mechanism.- I

A plate clamping mechanismembodying the invention in a preferred form will now be'described with reference a.

to the accompanying drawing, and the features forming the invention will then be' pointed out in the appended claims.

In the drawing:

FIG.l is an approximately axial line 11 of FIG. 3, of the plate clamping portion of the printing cylinder;

FIG. 2 is a section on the line 2-2 of FIG. 1, showing the operating mechanism;

FIGS. 3 and 4 are sections on the lines 33 of FIG. 1 and showing the parts in two different positions.

The plate clamping mechanism is carried in a rectangular groove or channel 1 which is formed in the cylinder body 2 in the usualvway. The mechanism comprises a supporting block 3 fitting in this groove and having a bore 4 which accommodates a plate clamping rod or shaft 5, the rod having clearance in the bore suflicient to accommodate the plate P and being supported in the bore by means of bearer rings 6 which are fixed to the rod 5 as by screws 7 and extend about two-thirds around the circumference of the rod so as to furnish the necessary support while not interfering with the plate.

A gap 8 is cut in the cylinder surface and into the bore 4 to accommodate the plate. This gap has on one side a rounded edge 9 to take the end 10 of the plate and this rounded edge connects to the surface of the bore 4 by a tangential plane surface 11, as shown in FIGS. 3 and 4. The other side of the gap comprises a somewhat rounded edge 12 which is positioned substantially tangent to a plane which is tangent to the rod 5 at approximately the point where the plane 11 joins the inner surface of the bore 4. The rod 5 has a longitudinal groove 13 accommodating a clamping plate 14, which is supported on plungers 15 carried in the rod 5 and movable diametrally thereof. The rod is bored, as indicated in FIGS. 3 and 4, having a smaller bore 16 adjacent the groove 13, which accommodates the plunger 15 and a larger bore 17 which accommodates the enlarged head 18 of this plunger and also receives a spring 19 thrusting against the head 18 and against the end of the bore 17. The bore 4 is cut back as indicated at 20 to form a recessed cam surface receiving the plunger head 18, so that in the unlocked position of FIG. 4, the clamping plate 14 may be drawn down against the bottom of the groove 13, while in the locked position of FIG. 3., this clamping plate will be moved up in the groove 13 for holding a plate end as described below. The groove 13 has a straight wall 21 against which the clamping plate 14 slides and an undercut beveled wall 22 which is parallel to the correspondingly beveled face 23 of the clamping plate 14, the sursection, taken on the i at 25, and the edge portion 27 being of such length as to insert readily in the gap and hook over the edge of gap 13, as indicated. It will be observed that the width of the gap 8 may be very narrow and need be only suflicient to accommodate the bent edge 25, which may be sprung slightly in passing through the narrowest point of the gap. With the part'sin the position of FIG. 4, the plate end 10 is first hooked over the gap edge 9 and the plate is" pulled around into approximately the position of FIG. -4. Thereafter, the bent edge 25 is pushed into the cylinder gap until the edge section'27 hooks in back of the edge of groove 13, behind the undercut gap wall 22. Rotation (clockwise) of the bar 5 pulls the edge of the gap 13 into the inside of the plate. bend 25, drawing the plate end around with the bar and under the other end 10 of the plate, where it lies against the flat surface 11.1 DUI: ing this rotation, the head 18 of plunger 15 rides up-on cam surface 20, thus pushing up the clamping plate 14 until it engages the plate end 27, as indicated in FIG..3'. Thereafter, as the-turning'continues, the plunger head 18 rides against the concentric surface of the bore 4, holding the plate end within the groove 13, as shown in FIG, 3, so that the plate is stretched around the cylinder and the required tension for holding it in position is developed. The edge 28 of the other end of the plate is spaced from the surface of bar 5 by approximately the thickness of the plate, so that the portion 26 which is pulled around on the bar in looking up the plate and which is very nearly tangent to the fiat surface 11, locks the other plate end 10 securely in position.

The mechanism for operating the bar 5 to lock and unlock the plates, comprises a worm wheel 30 fixed to the bar 5 and operated by a worm 31 which is fixed to a shaft 32 which is rotatable and slidable in sleeve elements 33 and 34, which are fixed in a bore 35 in the cylinder body 2 and clamping assembly body 3, frustoconical or Belleville spring elements 36 acting between V lower position on the shaft 32, until the plate is tensioned.

Further rotation of shaft 32, by reason of the helical pitch of the worm teeth, will cause the worm and shaft 32 to move axially outward against the spring 36, the visible protrusion of the end of shaft 32 thus indicating that the tensioning rotation of the bar 5 has been completed, and avoiding damage due to inadvertent application of excessive force on the wrench. The Belleville spring also acts as take-up mechanism if the plate should stretch after a period of operation.

As pointed out above, the insertion of the angle 25 involves merely pushing it into the gap 8, the acute-angled edge of the reel rod or shaft groove 13 automatically taking hold of the edge 27 as the reel rod is rotated from the position of FIG. 4 to that of FIG. 3. Similarly, as the rod is rotated back from the position of FIG. 3 to that of FIG. 4 to disengage the plate, the edge 27 by reason of the plate stifiness is automatically backed out of the groove 13 and passes through gap 8 with no difficulty.

its surface and an-sfiXially extending gap communicating with the bore, a reel rod fitting the said bore, having a grooveand clamping member within-pthe groove forrholding the printing plate end, and operating means for :the

said clamping. member comprising spring means forv urging the clamping member toward open position and cam means for forcing it into closing positiomlthe last said means comprising aplunger mounted diametrally in the said vreel rod and a cam surface formed in-the wall. of the said cylinder body bore, whereby rotating the reel rod to a plate end receiving position with relation to the said gap permits the said spring means to .open the clamping member and rotating it away from the said position causes the said cam surface to close the .said clamping member.

2. A printing cylinder plate clamping mechanism according .to claim- 1, in which the said .reel rod groove has an inwardly'diverging wall for receiving a plate lend bent .to an .acute angle around the adjacent edge of :the groove, and the plate gap has a lesser width than .the plate edge bent to the said angle, whereby the. pre-bent edge may he sprung through the gap and into thesaid groove.

3. A printing cylinder plate clamping mechanism according to claim 2, comprising aplate end supporting sur, face extending from anedge of the gap tangent .to the bore, whereby a plateend held in the said reel rod groove engages against an opposite end of the plate, forcingthe same against the said tangent surface for holding it in position.

4. A printing cylinder plate .clamping mechanism according to claim 3, in which a continuation of the said tangent surface clears the other side of thegap ,b-yabout twice the thickness of the plate.

5. A printing cylinder plate clamping mechanism according to claim 4, in which the said plunger engages a concentric cylindrical portion of the cylinderbody bore in clamping position and thesaid concentric cylindrical portionextends beyond the point of said engagement to permit further tightening, and comprising yielding means for holding the reel rod in plate clamping position with predetermined pressure, whereby the angular position of the reel rod may vary without varying the clamping action.

References Cited in the file of this patent UNITED STATES PATENTS 2, 7,621 Neilson -.---a--.--.--- M y .9. :939.

2,186,764 Meise'l j, Ian. 9, 1940 2,279,204 Neilson Apr. ,7, 19.42

2,541,254 Huck et a1. Feb. 13, 19,51

2, ,4 Dutro De 11, 1

2,900,904 Hantscho 7., Aug. 25, 1959 FOREIGN PATENTS 

